The fear of attacks by Islamic militants in Nigeria is spreading south to the commercial capital, Lagos, where city buses are being checked for bombs. A group that says it is fighting for a separate Islamic state is thought responsible for a series of attacks across the north.

Bomb attacks and ambushes in the northern city of Maiduguri have indefinitely closed the university there and led to an exodus of civilians, some of whom are newly unemployed motorbike taxi drivers after all motorbikes were banned in Maiduguri because Islamic militants were using them to throw bombs.

The Islamic sect Boko Haram recognizes neither Nigeria's constitution nor the federal government and says it is fighting for a separate nation in the north, ruled by Islamic law.

The group bombed national police headquarters in Abuja and a church just outside the capital, which is now under a limited curfew with all bars and movie theaters closed by 10 p.m.

The fear of Boko Haram attacks is now spreading south to Lagos, following a text message purportedly sent by the group warning people not to take government buses because they are a target.

The managing director of LAGBUS, Yemi Odubela, told the News Agency of Nigeria that the firm is aware of the threat and is asking passengers to remain vigilant and cooperate with spot checks of their bags.

At the Eko roundabout bus stop on Victoria Island, this passenger says her bags were checked when she boarded the LAGBUS.

"They have been checking us before we entered at Leventis," she said. "They checked us to see if anybody is carrying any equipment inside their bags. So they checked us before we entered. Men check men. Women check women.”

STEARNS: "Did that make you feel safer then?”

BUS PASSENGER: "Yeah. Yeah. Yeah. We are afraid. We are afraid. Everybody is afraid to enter, you see that blue color [bus] and this red color [bus]. We are afraid. They check under all the seats before we entered. So maybe there is something they hide under the seats. There is nothing under [the seats].”

This man, getting off the #55 LAGBUS, says he does not believe the Boko Haram threat.

"They have been operating," he said. "Even when they have been bombing, have they been giving warnings? No. They have not been giving warnings. They do it. So I want to believe that people are just trying to use that to cause confusion.”

With heavy rains in Lagos, this woman says her car will not make it through the flooding, so she has to take the bus, despite the threat.

"I have no choice," she said. "Because of the rain, I have no other transport means to get to this place.”

This passenger says Boko Haram will find it far harder to operate in the south.

"We will continue to take the bus because there is security in Lagos," said the passenger."I don't believe they will come to this place. I just call it a threat. They can't come down to the south. We will check them here. LAGBUS is even better because at LAGBUS you queue. So you can check anybody who enters that LAGBUS. So if it just an ordinary bus like this one that everybody jumps inside it is a different thing.”

President Goodluck Jonathan has offered to open talks with the group, but Boko Haram leaders have so far refused, saying they cannot meet with security forces that are trying to destroy them.